1. Field of the Invention
The present invention relates to an ultrasonic endoscope, which uses ultrasonic waves for the diagnosis of a diseased tissue. Especially, the present invention relates to a construction of the portion of the point in the endoscope.
2. Description of the Related Art
In the ultrasonic endoscope, an ultrasonic probe having ultrasonic wave vibrators is provided at the distal end of the endoscope. The ultrasonic probe sends ultrasonic waves and receives echoes of the sent ultrasonic waves.
For the scanning method, a radial scanning or a linear scanning is used. For example, when diagnosing an organ (body-cavity), into which the ultrasonic endoscope cannot be inserted, the radial scanning is performed. The endoscope is inserted toward an organ adjacent to the observed organ, ultrasonic waves are sent radially from the ultrasonic probe. Conventionally, a mechanical-type radial scanning is applied, where a series of ultrasonic wave vibrators is aligned along an axis of the probe and revolves on the axis to send the ultrasonic waves radially.
However, in the case of the mechanical type radial scanning, a color-image, partially colored by Red (R), G (Green), B(Blue), which is effective for diagnosis of the diseased areas, cannot be displayed on the monitor.
Further, while manipulating the bending portion, various forces act on signal transmitting members for transmitting signals associated with the ultrasonic waves and the echoes. Therefore, a greater durability for the bending motion is required for the signal transmitting members provided in the distal end of the endoscope.
Therefore, an object of the present invention is to provide an ultrasonic endoscope that is capable of obtaining an observed-image for diagnosis, and further that is durable in its bending motion.
An ultrasonic endoscope according to the present invention is an endoscope for performing electronic radial scanning. A bending portion formed in a tube is connected to the point of a flexible tube, which is inserted in a body, or organ. The flexible tube is normally connected to a manipulator portion of the endoscope, and an operator, such as a doctor, bends the bending portion by manipulating a manipulating knob, which is operatively connected to the bending portion. Namely, the bending portion bends by remote control.
An ultrasonic probe for the electronic radial scanning is operatively connected to the bending portion. For example, a solid point-base portion is connected to the bending portion and the ultrasonic endoscope is attached to the point-base portion.
The ultrasonic probe has a plurality of ultrasonic wave vibrators, which are arranged circumferentially to perform the electronic radial scanning. The plurality of ultrasonic wave vibrators send ultrasonic waves radially around a center axis of the ultrasonic probe and receive echoes of the ultrasonic waves.
According to the present invention, a flexible circuit board is provided in the endoscope. The flexible circuit board transmits signals associated with ultrasonic waves and echoes, so that an ultrasonic-image, representing a section-image in the body, is obtained at the ultrasonic wave diagnosis apparatus. As electronic scanning (not mechanical scanning) is performed, an ultrasonic color-image is obtained as required by simultaneously sending multiple ultrasonic waves, each frequency of which is different, or an ultrasonic pulse-width image is obtained by coloring in accordance with contrast of the echoes. These images cannot be obtained by mechanical radial scanning.
In the bending portion, the flexible circuit board is constructed of a plurality of flexible circuit board strips so as to allow a bending motion, namely, to be capable of withstanding the bending motion. The plurality of flexible circuit board strips extends along a central axis of the bending portion. The signal-transmitting member in the bending portion is composed of a plurality of strip-shaped flexible circuit boards, which prevent snapping while the bending portion is manipulated. The plurality of flexible circuit board strips enables the circumferential arrangement of the ultrasonic wave vibrators, namely, the electronic radial scanning. Note that, the width of each flexible circuit board strips is defined in accordance with a radius of the bending portion.
According to the present invention, the plurality of flexible circuit board strips is durable for the bending motion of the bending portion. Speaking concretely, constructions that prevent the flexible circuit board strips from snapping flexure and strengthen the flexible circuit board strips themselves, are shown. Note that, the snapping flexure represents that the flexible circuit board strips are sharply bent, broken or shaped in sharp-wave, which is like a saw wave.
While the bending portion is manipulated, compressing and extending forces operate along the central axis, against the plurality of flexible circuit board strips. Not to cause the snapping flexure, rather to cause smooth and gently flexure when the compressing and extending forces operate, preferably, flexible protecting members are provided. The flexible protecting members extend along the central axis respectively and coat at least one corresponding flexible circuit board strip among the plurality of flexible circuit board strips, respectively. As the thickness of the section of the bending portion increases relative to the flexible circuit board strips, the bending-resistance increases, so that the flexible circuit board strips flexes loosely and smoothly, in other words, flex gently along the central axis. To tightly coat or cover the flexible circuit board strips, preferably, heat shrinking tubes are used as the flexible protecting members. The heat shrinking tubes tightly coat the plurality of flexible circuit board strips after the heat shrinking process. To obtain more durability, preferably, a plurality of bundles, each of which is composed of at least two flexible circuit board strips, is formed using the plurality of flexible circuit board strips. The plurality of bundles may then be coated by using a flexible protecting member for each bundle.
In order not to cause snapping, preferably, the first printed wiring printed on the plurality of flexible circuit board strips is bolder than the second printed wiring printed on a connecting portion of the flexible circuit board, which is connected to the ultrasonic probe. In general, the number of a signal lines of the second printed wiring is determined by the number and arrangement intervals of the ultrasonic wave vibrators. To obtain high-quality ultrasonic-images, it is necessary to arrange a lot of ultrasonic wave vibrators and to have the thinnest printed wiring possible for the second printed wiring. In the bending portion, the first printed wiring becomes bolder than the second printed wiring, which prevents the plurality of flexible circuit board strips from snapping when the plurality of flexible circuit board strips flex.
The flexible circuit board may be formed from a single rectangular flexible circuit board. In this case, the flexible circuit board is formed by partially cutting a single rectangular flexible circuit board such that a plurality of flexible circuit board strips are formed and then rounding the cut rectangular flexible circuit board so as to form a cylindrical shape. To make the first printed wiring bolder, the length of the cut portion of the rectangular flexible circuit board is longer than the length of the connecting portion.
To cause smooth flexure of the plurality of flexible circuit board strips when the compressing and extending forces operate, preferably, flexible sheets that extend along the central axis are provided. Each of the flexible sheets is tightly piled on a corresponding flexible circuit board strip among the plurality of flexible circuit board strips. As the thickness of the bending portion section increases compared to the flexible circuit board strips, the bending-resistance increases, so that the flexible circuit board strips flex smoothly and gently along the central axis. To tightly coat, or cover the flexible circuit board strips, preferably, heat shrinking tubes for tightly coating the plurality of flexible circuit board strips and the flexible sheets by a heat shrinking, are provided.
To cause smooth flexure of the plurality of flexible circuit board strips when the compressing and extending forces operate, preferably, elastic members that extend along the central axis are provided. Each of the elastic members tightly touches a corresponding flexible circuit board strip among the plurality of flexible circuit board strips. As the elastic members absorb the compressing and extending force, the flexure of the flexible circuit board strips become smooth.
In general, the bending portion is composed of a series of ring-shaped segments, which are jointed to each other by hinges. In order not to pinch the plurality of flexible circuit board strips between the series of ring-shaped segments during a bending motion, preferably, each of the elastic members touches the corresponding flexible circuit board strip such that the corresponding flexible circuit board strip is between its elastic member and the central axis in the section of the bending portion. Namely, the elastic members are arranged closer to the circumference than the plurality of flexible circuit board strips. To tightly coat the plurality of flexible circuit board strips, heat shrinking tubes for tightly coating the elastic members and the plurality of flexible circuit board strips by heat shrinking, may be provided. As for the elastic members, preferably, each of the elastic members is an elastic wire, or a coil spring. In the case of elastic wire having elastic characteristics, for example, each of the elastic members is composed of one of the following; metal twist wires, a single metal wire having elastic characteristics, and super-elasticity alloy steel.